Spectroscopic (FT-IR, FT Raman and UV-Vis), Quantum Computational and Molecular Docking studies on Propylthiouracil

Abstract

The vibrational spectroscopic (FT-IR and FT Raman) and electronic properties (UV-Vis) have been investigated experimentally at room temperature and were compared with quantum computational calculations using DFT and TD DFT techniques with 6-311++G(d,p) as the level of theory by GAUSSIAN 09W. The fundamental modes of vibrations were carefully assigned which were compared with experimental vibrations. Theoretical information on the optimized structure, Natural Bond Orbitals (NBO) and NLO were also obtained. The delocalization of electrons due to hyper conjugation was understood using NBO analysis. Data on the stabilization of the molecule due to different transitions were explained using this analysis. Dipole moment, polarizability and first order hyperpolarizability calculations were done. These revealed that the compound may be a suitable NLO material. Thermodynamic properties such as entropy, enthalpy and specific heat of molecule over a temperature range 100-1000 K were studied. The compound was found to be stable for higher temperature range. Local reactivity sites of the compound were studied using Molecular Electrostatic Potential (MEP) and Localized Orbital Locator (LOL) studies, while Pauli exchange repulsion effect was used to obtain Electron Localization Function (ELF). Hence the electrophilic and nucleophilic sites of the molecule were elucidated. A Hirshfeld surface was obtained to study the intermolecular interactions. The HOMO-LUMO energy gap was calculated and compared with the experimental data obtained and was found to be in good agreement. An electrophilicity index of 3.439 explains that the molecule is biologically active. The drug-like nature of the molecule was confirmed using Lipinski’s rule of five. Hence, the protein binding orientations and energies of protein-ligand complexes were predicted using molecular docking studies.